Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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TITLE: UNWIND AND FEED SYSTEM FOR ELASTOMERIC THREAD
BACKGROUND
This invention relates generally to unwind devices and feed controls which are
used for
unwinding highly elastic and tacky threads from a spool/package of such
thread, and feeding
such threads into a manufacturing process which uses and/or further processes
such threads.
In general, a spool/package of the desired thread is mounted on an unwind
stand.
Thread from the spool/package is threaded by hand into the manufacturing
process at process
start-up. As the manufacturing process which uses the thread proceeds, thread
is pulled from
the package and guided to the manufacturing process.
One method of unwinding and feeding thread from a spool of such thread in
manufacturing processes is referred to as a "rolling unwind". In the rolling
unwind method, the
package/spool is mounted in an unwind stand with the axis. of rotation of the
package/spool
oriented generally perpendicular to the direction in which the thread is to be
drawn from the
package. The spool/package turns at a speed which is related to the unwind
speed, allowing for
a desired feed rate, so as to feed the thread from the rotating package along
a line which
generally approximates a perpendicular to the axis of rotation of the spool of
thread and which is
generally tangent to the outer surface of the thread on the spool.
When a first package of the thread is exhausted, the manufacturing process is
shut
down. The first package is removed. A second package is installed and threaded
up.
A major disadvantage of a rolling such unwind operation is that the
manufacturing
process must be shut down every time a spool of thread is exhausted. Since the
manufacturing
process typically draws a plurality of material feeds from a plurality of
source packages of thread,
shutting down the entire manufacturing process when a single source is
exhausted typically
results in substantial down-time losses and substantial production of scrap
during shut-down and
start-up. Accordingly, in one method of controlling the amount of down-time,
when one roll has
been exhausted and the process is shut down, all rolls relating to that
process are replaced with
full rolls irrespective of the amount of thread remaining on ,a given spool.
The result is the
wasting of the thread which remains on those spools which are not exhausted.
Another method of unwinding and feeding thread from the spool is known as the
overend
take-off method (OETO). In the overend take-off method, the package of thread
is fixedly
mounted on the unwind stand so that the axis of rotation of the package is
pointed in the general
direction of the path to be traversed by the thread as the thread is drawn
from the package.
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However, in the overend take-off method, the package of thread does not rotate
as the thread is
being drawn from the package. Rather, the thread comes off the spool over the
end of the
spool. As the thread leaves the spool, the locus of departure rotates about
the circumference of
the spool, such that the path initially traversed by the thread is rotational
in nature. At lower
speeds, the thread gets just past the 12 o'clock position on the spool and
drops to the 6 o'clock
position. At higher speeds, the thread rotational action embodies centripetal
forces which are
acting essentially perpendicular to the general direction of travel of the
thread, whereby the
thread leaving the spool looks much like a loop, a jump rope, or hoop, or
ballooning action. All
such actions are intended to be included in referring to the action of the
thread as a "loping"
action. Such loping action must be controlled, damped out, so that the thread
can be guided at
controlled tension and direction along a predetermined path, in such a manner
as to be
delivered, fed, to the manufacturing process at a controlled and generally
constant, though
changeable, level of tension. In achieving the generally constant level of
tension, the tension
spikes and other tension variations, which are inherent in, the overend
dispensing of such a
sticky thread, must be dissipated within the unwinding and feeding mechanism.
Since the spool is fixed in location, the operator can tie the trailing end of
a first active
spool to the leading end of a next-in-line reserve spool such that the tail
end of an active spool
automatically transfers the feed to the reserve spool when the active spool is
exhausted,
whereby there is no need to stop the manufacturing process to change spools.
Accordingly,
overend feeding inherently avoids the above-noted wasting of thread on changed-
out spools
where the thread supply has not all been used up, as well as the shut-down,
start-up times
associated with such spool change-outs Thus, overend feeding embodies built-in
cost savings
related to both materials usage and production output, whereby overend
unwinding is a desirable
technology for unwinding tacky threads and feeding such tacky threads into a
manufacturing
process.
However, overend unwinding and feeding technology has its own challenges to
successful operation. In conventional overend unwind technology, the thread
coming off the
spool is first fed through a circular ceramic eye to suppress the jump rope,
hoop, ballooning
characteristic of the thread coming off the spool. In a creel which supports
and controls a
plurality of simultaneously-active threads, each thread is initially fed
through a separate such
circular ceramic eye, and the threads are fed from the initial circular
ceramic eyes to a common
driven roll. The driven roll treats all of the threads the same. Namely, each
thread passes over,
through its own groove on the driven roll, whereby all of the threads are
individually treated to a
common roll drive and/or retardation.
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The purpose of such driven roll is to capture and eliminate laterally-directed
kinetic
energy in a thread and to absorb and eliminate longitudinally-directed
force/tension variations in
the thread. Tension both before and after the driven roll can vary widely
depending on winding
tension in the spool, as well as the experience of the thread between the
spool and the driven
roll. The result is that thread speed is controlled at the driven roll, while
tendon continues to vary
from thread to thread in a given unwind operation on an unwind stand. But
there is no sensing,
no direct control, of the tension in individual ones of the threads leaving
the driven roll. Nor is
there any sensing, any direct control, of the tension in the collective
combination of the threads
leaving the driven roll. And there is no control of tension in the threads
between the driven roll
and the manufacturing nip where the threads enter the product assembly
operation.
Still referring to conventional overend technology, from the driven roll, the
threads make
their ways, along pre-determined paths, to respective entrance points into the
manufacturing
process. Given the layout of a typical manufacturing line for personal hygiene
products where
such threads are commonly used, there is commonly no space for the unwind
creel immediately
adjacent the point of entry of the threads into the manufacturing process.
So a common location for the unwind creel is across an aisle or walkway from
the
manufacturing process line. Thus, the distance which the thread travels, from
the driven roll on
the unwind creel, to the point of entry at a nip in the manufacturing process,
is several meters,
typically about 10 meters. Further, each thread passes over a number of
turning rolls and guides
in traversing along the thread path, from the unwind creel to the
manufacturing process,
including across the aisle/walkway. In such traversing, each thread passes
over a separate and
distinct set of guides and rolls, separate and distinct from the set of guides
and rolls traversed by
any other thread.
Each such turning roll or guide adds a measure of tension to the respective
thread. By
the time the thread gets to the process nip, the tension in the thread has
been changed by its
contacts with the respective guides and rolls, such that the tension on a
given thread entering
the nip at the manufacturing process is different from the tension on that
same thread as the
thread leaves the driven roll on the creel. Further, the tension increment at
each such guide or
roll is different depending on surface characteristics of that guide/roll,
efficacy of the bearings if
any, any dirt or lubricant which may have accumulated on the surface of the
guide or roll, any dirt
or other detritus which may have gotten into roll bearings, or the like.
Overall, in conventional
overend technology, the tension entering the manufacturing nip is not well
controlled by
controlling the speed or tension at a driven roll which is close to the
elastic fiber spool and
relatively farther from the manufacturing nip.
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A further problem with conventional unwind systems is that the ceramic eye,
which is first
encountered by the thread as the thread leaves the spool, is motionless, and
thus exerts a static
friction drag on the loping, jump-rope, thread which is passing through the
eye. Where, as here,
the thread is an elastomeric fiber such as spandex thread, which is bare and
substantially free of
finish, the fiber-to-fiber and fiber-to-ceramic frictional characteristics are
significantly higher than
with covered or lubricated fibers. Thus, a significant drag results when this
very tacky thread is
pulled across the static ceramic surface of the eye guide. The rotational
ballooning action of the
thread, as the thread is pulled from the package, causes the thread to be
dragged along the
edges of the ceramic eye guide rather than straight through the center of the
eye. The frictional
drag, between the static eye and the tacky thread, is exacerbated as the angle
of wrap of the
thread around the edge of the static eye guide is increased. Because of the
jump-roping
motions, the angle of contact with the static ceramic eye is cohstantly
changing. Therefore, the
amount of friction at the static eye is constantly changing, resulting in
alternating large and
sudden increases and decreases in tension, and accompanying sticking and
slipping of the
thread at the ceramic eye. The resulting friction is neither constant nor
predictable, whereby the
thread is also experiencing ongoing and constant substantial changes in speed
of advance of
the thread along the thread path.
While this invention is capable of handling a wide variety of thread types,
the advantages
of this invention are readily experienced in handling unwind and transport of
untreated
elastomeric fiber thread. Such elastomeric fiber thread is uncoated, having no
lubricant, no oil
on its surface. The thread can be an "as spun" thread, or a rewound thread.
The rewound
thread has a much more consistent drag, tension as it is unwound from the
spool, than an "as
spun" thread. The thread has a size in the range of about 200 decitex to about
2000 decitex,
typically about 400 decitex to about 1000 decitex.
Typical tension in the thread as it leaves the package can be as little as
about 2 grams
for a rewound thread. For an as-spun thread, the tension as the thread leaves
the package
typically averages about 5 grams to about 20 grams. However, the tension
varies substantially
depending on stage of the unwind at which the tension is being measured. For
example, where
the average tension e.g. over a 10 minute period is measured as 6 grams at the
outside of the
package, e.g. when unwinding of that package has just started, the average
tension just before
the unwinding reaches the core or end of the package is substantially higher
such as 12 grams.
When real-time tension is measured in very short increments such as at 0.1
second
increments, thread-to-thread sticking reveals substantially greater spikes in
tension differences,
from a tension of effectively zero to a tension as high as 30-40. grams or
higher, all in the course
of e.g. releasing a single wrap from the spool.
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The overall objective of the thread feed is to convert a roll of wound up
elastomeric fiber
thread, from a highly variable tension as the thread leaves the'spool, to a
thread which feeds into
the manufacturing nip at a constant and controllable tension of about 80 grams
to about 250
grams, depending on the thread decitex and the finished manufacturing product
specifications.
Thus it is desired to provide an overend thread unwind system for elastomeric
and tacky
threads which is effective to capture the loping, jump rope, activity of the
thread as the thread is
unwound from the spool.
It is a further desire to capture the loping, jump rope, activity of the
thread while applying
a minimal amount of friction and/or drag force on the thread.
It is still further desirable to capture the loping, jump rope, thread with a
travelling e.g.
rotating or rolling, capture device, such that the thread does not necessarily
routinely travel over
any static surfaces.
It is further desirable to capture the loping, jump rope thread with rotating
devices which
are closed on opposing ends of the device such that the thread cannot come off
the capture
device by moving laterally along the axis of rotation of the device and past
the end of the device,
and whereby the thread will be prevented from moving off the device by the end
closure
structure.
It is yet further desirable to exert a first-stage tension control input on
the thread at the
unwind creel close to the elastic thread package and to exert a second-stage
tension control
input on the thread proximate the manufacturing nip, and whereby the thread
traverses no more
than a minimal number of thread guides, if any, between the second tensioning
device and the
manufacturing nip.
It is still further desirable to provide a manufacturing operation wherein a
tacky thread is
fed into the product assembly operation at a constant tension, controlled by
an unwind and feed
system which exerts a final tension control on the thread at an up-stream
location proximate the
entrance of the thread into the product assembly operation, such that the
thread typically
experiences no more than three, optionally no more than one or two, guide
surfaces after
departing the final tensioning device, and wherein the final tensioning device
is no more than
three meters, optionally no more than one or two meters, from entrance of the
thread into the
manufacturing nip.
Tensioning devices such as the BTSR brand KTF-RW constant tension feeder are
typically used as stand-alone devices. Parameters such as tension setpoint,
tension deviation
alarm window, system responsiveness / reactivity, etc. are usually set at each
individual device.
Dynamic status values such as tension feedback, drive current, drive
temperature, and system
health status are usually only available for display on each tensioning device
drive module.
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Hand-held programming devices and PC-based software systems exist which can be
used for the initial setup of the tensioning devices. However none of such
devices provide for
integration of the tensioning devices with the industrial programmable logic
controllers (PLC's)
which are standard in automated manufacturing processes.
Standard practices and controls procedures for most automated industrial
manufacturing
processes, especially in the personal care industries, such as the hygiene
industry, the baby
diaper industry, and the adult incontinent industry, require complete
integration of all devices and
sub-systems which participate in the manufacturing operation. All operating
parameters for all
devices in the entire manufacturing line must be set and monitored from a
central operator
interface, usually a touch screen, which in turn is connected to the central
PLC. The central PLC
manages all of the setpoint parameters and monitors feedback and status data
from all devices
on the production line.
Conventional, off-the-shelf tensioning devices require direct or local input
of control
parameters into the individual devices, and thus do not conform to such
centralized control
scheme, and are therefore prohibited from use in many manufacturing
environments. There is a
need for a means to fully integrate the control and monitoring of setpoints,
feedback, and status
values of tensioning devices into an automated manufacturing system.
Production lines used in the manufacture of hygiene, baby diaper, adult
incontinent, and
related products are complex, with highly sophisticated control systems. Due
to the complexity
of the programming in the main system PLC, it is a difficult, time-consuming,
and expensive
process to make significant program changes to a functioning production line.
Therefore, when
the new accessory or sub-system, namely the elastic feeding equipment of the
invention is
added to the production line, it is generally preferable for the time-critical
functions of such sub-
system to be handled by a secondary controller which then communicates with
the main PLC.
Setpoint information for the subsystem is sent to the secondary controller
from the main PLC.
Feedback and status information are sent from the secondary controller to the
main PLC.
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SUMMARY OF THE INVENTION
In general, this invention provides an overend unwind system which is
especially adapted
for unwinding tacky elastomeric fiber threads such as uncoated spandex thread,
damping out the
ballooning affect and major tension spikes of the thread shortly after the
thread leaves the spool,
applying a first coarse tension control on the thread in the vicinity of where
the thread leaves the
spool, feeding the unwound thread to a nip in a manufacturing operation, and
applying a second
refining tension control to the thread adjacent where the thread enters the
manufacturing nip.
The unwind system thus smoothes out tension variations in the unwound thread
using a such
two-stage tension-control system, wherein the first-stage coarse-tension
control reduces tension
variations along the length of the thread and the second-stage fine-tension
control further
reduces and/or eliminates the remaining tension variations and sets the thread
tension to the
desired value proximate the location where the thread enters the product
assembly operation.
Thus, the 2-stage tension control system of the invention acts like an
extended-length 2-stage
shock absorber, effective to substantially dampen the tension variations which
exist in the thread
as the thread leaves the spool. With the exception of a tension sensor, all
thread guide surfaces
encountered by the thread after leaving the spool, and while the thread is
under tension, are
moving surfaces, such that the tensioned thread, using apparatus and processes
of the
invention, never passes over a static guide surface other than the tension
sensor, and thereby
experiences a reduced level of drag as the thread traverses its thread path
from the spool to the
manufacturing nip.
In a first family of embodiments, the invention comprehends an unwind and feed
system
adapted for overend unwinding of an elastic thread from a package of such
thread in a
manufacturing process, and feeding such unwound thread in a downstream
direction, along a
thread feed path, to a product assembly operation, the unwind and feed system
comprising a
frame, including a device adapted to hold a package of thread; and a plurality
of thread guides
disposed along the thread feed path, between such package of such thread and
such product
assembly operation, the plurality of thread guides being adapted to guide such
thread along the
thread feed path, the plurality of thread guides comprising (i) a first thread
guide closest to the
thread package holder, (ii) a second thread guide downstream from the first
thread guide, along
the thread path, and (iii) a third thread guide downstream from the second
thread guide, along
the thread path, all of the plurality of thread guides, between such package
of such thread and
such manufacturing process, comprising moving-surface thread guides such that,
in routine
ongoing operation of the unwind and feed system, other than any tension
sensor, such thread
encounters only moving-surface thread guides.
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In some embodiments, the thread guides are adapted to move thread contact
surfaces of
the thread guides at surface speeds which approximate speeds of movement of
such thread.
In a second family of embodiments, the invention comprehends an unwind and
feed
system adapted for overend unwinding of an elastic thread from a package of
such thread in a
manufacturing process, and feeding such unwound thread in a downstream
direction, along a
thread feed path, to a product assembly operation, the unwind and feed system
comprising a
frame, including a device adapted to hold a package of thread; a plurality of
thread guides
disposed along the thread feed path, between such package of thread and such
product
assembly operation, the plurality of thread guides being adapted to guide such
thread along the
thread feed path; and a tension control system, adapted to control tension in
such thread along
the thread feed path, including a terminal tensioning device which acts on
such thread in the
thread feed path within 3 meters of a locus where the thread feed path joins
such product
assembly operation, the terminal tensioning device being adapted to
intentionally modify tension
in such thread.
In some embodiments, the terminal tensioning device is adapted to modify
tension in
such thread to an extent greater than tension modifications which are
conventionally imparted to
such thread by conventional rolling-surface thread turning devices.
In some embodiments, the terminal tensioning device actively modifies tension
in such
thread.
In some embodiments, the terminal tensioning device has a target setpoint, and
wherein
the setpoint is adjustable thereby to increase or decrease a setpoint tension
at which such
thread leaves the terminal tensioning device.
In some embodiments, the terminal tensioning device comprises a closed-loop
tensioning
device which is capable of actively increasing or decreasing tension in such
thread to achieve a
desired tension in thread exiting the terminal tensioning device.
In some embodiments, the terminal tensioning device comprises a closed loop
braking
device which is capable of actively increasing tension in such thread to
achieve a desired final
tension in thread exiting the terminal tensioning device.
In some embodiments, all of the thread guides, except any tension sensor, are
moving/rolling thread guides.
In some embodiments, the thread guides are adaptedto move thread-contact
surfaces of
the thread guides at surface speeds which approximate speeds of movement of
such thread.
In some embodiments, the invention further comprises an operator control
station
communicating with the tension control system, and adapted to send at least
one of tension
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value, enable or disable switching signals, and alarm setp9int values to the
tension control
system, and/or to receive at least one of feedback tension values and status
information from the
tension control system.
In some embodiments, the unwind and feed system is operationally connected
into a
manufacturing system, the manufacturing system comprises a main controller,
and the main
controller communicates with the unwind and feed system through the operator
control station.
In some embodiments, the main controller has an operator interface, and an
operator of
the manufacturing system can communicate with the tension control system, and
thereby control
the terminal tensioning device, through the operator interface.
In a third family of embodiments, the invention comprehends a manufacturing
system,
comprising a plurality of devices which collectively control passage of an
elastic thread along a
thread path from a package of such thread to a destination, including a thread
tensioning device;
a control system adapted to control operations of the plurality of devices,
the control system
comprising (i) a main industrial-grade programmable logic controller which
provides primary
monitoring and operational control, through a primary operator interface, of
the manufacturing
system, and (ii) a secondary controller, adapted to communicate with the
thread tensioning
device, and the main industrial-grade programmable logic controller using
industrial-grade
communications protocol, whereby the secondary controller enables
communication between the
main programmable logic controller and the thread tensioning device, such that
an operator of
the manufacturing system can control operation of adjustment capabilities of
the thread
tensioning device from the primary operator interface.
In some embodiments, the manufacturing system manufactures personal care
hygiene
products.
In some embodiments, the secondary controller is adapted to send at least one
of
tension value, enable or disable switching signals, and alarm setpoint values
to the tensioning
device, and/or to receive at least one of feedback tension values and status
information from the
tensioning device.
In some embodiments, the secondary controller translates value-based messages
received from the main controller into protocol and/or format which can be
received and
understood by the thread tensioning device and sends such value-based
information to the
thread tensioning device, and receives messages from the thread tensioning
device and
translates such messages received from the thread tensioning device into
protocol and/orformat
which can be received and understood by the main controller, and sends such
translated
messages to the main controller.
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In some embodiments, the main controller commuilicates directly with the
thread
tensioning device regarding on/off switching-type information, without passing
such on/off
switching-type information through the secondary controller.
In some embodiments, all communications between the main controller and the
thread
tensioning device pass through the secondary controller, and is sent from the
secondary
controller to the thread tensioning device as on/off switching signals.
In some embodiments, all communications between the main controller and the
thread
tensioning device, including value messages and on/off messages, pass through
the secondary
controller, and wherein value messages received by the secondary controller,
from the main
controller, are translated by the secondary controller into protocol and/or
format which can be
received and understood by the thread tensioning device.
In some embodiments, the secondary controller sends raw data back to the main
controller.
In some embodiments, the secondary controller sends summary information to the
main
controller.
In some embodiments, the secondary controller stores in non-volatile memory
certain
historical operating information regarding thread tension, and which operating
information is
received from the thread tensioning device.
In a fourth family of embodiments, the invention comprehends an unwind and
feed
system adapted for overend unwinding of an elastic thread from a package of
such thread in a
manufacturing process, and feeding such unwound thread in, a downstream
direction, along a
thread feed path, to a downstream operation, the unwind andfeed system
comprising a frame,
including a package holding device adapted to hold a package of thread; a
thread capture
assembly adapted to capture loping thread being drawn overend off such package
of thread, the
capture assembly comprising (i) first and second rolling captuie devices
arranged at a generally
common distance from such package of thread and serving as initial contact
elements for such
thread being drawn overend off such package of thread, the first and second
rolling capture
devices having respective first and second axes of rotation which are parallel
to each other and
reside in a common plane, and (ii) at least a third rolling capture device
proximately downstream
from the first and second rolling capture devices, the third rolling capture
device having a third
axis of rotation generally perpendicular to the axes of rotatiOn of the first
and second rolling
capture devices, the first, second, and third rolling capture devices
collectively capturing both
horizontal and vertical vectors of such loping thread, the invention further
comprising a plurality
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of thread guides disposed along the thread feed path downstream of the thread
capture
assembly, and between the thread capture assembly and such product assembly
operation.
In some embodiments, the invention further comprises a fourth rolling capture
device
located downstream from the third rolling capture device, the fourth rolling
capture device having
a fourth axis of rotation generally parallel to the third axis of rotation of
the third rolling capture
device.
In some embodiments, the third rolling capture device is located generally
between the
fourth rolling capture device and the first and second rolling capture
devices.
In some embodiments, the first, second, and third rolling capture devices are
all elongate
rollers.
In some embodiments, the first and second rolling capture devices are elongate
rollers,
and the package holding device is oriented so as to direct a central
rotational axis of a package
of thread, mounted on the holding device, at an angle of about 20 degrees to
90 degrees from
the common plane.
In some embodiments, the first, second, third, and fourth rolling capture
devices are all
elongate rollers, and the package holding device is oriented so as to direct a
central rotational
axis of a package of thread, mounted on the holding device, at an angle of
about 20 degrees to
90 degrees from the common plane.
In some embodiments, the first and second elongate rollers are disposed in a
vertical
orientation in close proximity to each other, and the third and fourth
elongate rollers are disposed
in horizontal orientations in close proximity to each other, with the third
roller between the fourth
roller and the first and second rollers, such that a thread advancing from
such thread package
first encounters at least one of the first and second rollers, and
subsequently encounters the
third roller, and after encountering the third roller encounters the fourth
roller.
In some embodiments, the first and second thread capture devices have primary
affect
on reducing magnitude of a first pair of opposing vectors of kinetic energy in
such loping thread
while having lesser affect on second vectors acting perpendicular to the first
pair of opposing
vectors of kinetic energy, and wherein the third thread capture device has
primary affect on
reducing magnitude of second vectors acting perpendicular to.the first pair of
opposing vectors.
In some embodiments, the first and second elongate rollers have primary affect
on
reducing magnitude of a first pair of opposing vectors of kinetic energy in
such loping thread
while having lesser affect on second vectors acting perpendiCular to the first
pair of opposing
vectors of kinetic energy, and wherein the third and fourth elongate rollers
have primary affect on
reducing magnitude of second vectors acting perpendicular to the first pair of
opposing vectors.
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In some embodiments, all of the thread guides downstream of the thread capture
assembly, except for any tension sensor guide, are rolling thread guides.
In some embodiments, all of the thread guides downstream of the thread capture
assembly, except for any tension sensor guide, are rolling thread guides.
In some embodiments, the invention further comprises an un-powered rotating
brake
disposed downstream of the capture assembly.
In some embodiments, the thread passes from the fourth rolling capture device
to the
brake, as a next thread-controlling device during normal operation of the
unwind and feed
system.
In some embodiments, the invention further comprises a threading device
between the
fourth rolling capture device and the rolling brake and wherein such thread
does not touch the
threading device during normal operation of the unwind and feed system.
In some embodiments, the thread passes through the first and second upright
elongate
rollers as the initial contact elements after leaving such paCkage of thread,
and the first and
second upright rollers act primarily on horizontally-directed vectors of the
loping thread and
secondarily on vertical vectors of such loping thread, and the axes of
rotation of the third and
fourth rollers are in a common, generally horizontal plane, and the thread, in
proximity to the first
and second rollers, passes along a generally horizontal path onto the third
elongate roller, turns
around the third roller and passes thence onto the fourth roller, and turns
around the fourth roller
and exits the fourth roller toward, and next encounters a rolling brake
disposed downstream of
the capture assembly.
In some embodiments, the rolling brake is an un-powered brake, optionally a
magnetic
brake.
In some embodiments, the thread guides are moving-surface thread guides and
the
thread guides are adapted to move thread contact surfaces of the thread guides
at surface
speeds which approximate speeds of movement of such thread.
In some embodiments, the invention further comprises a thread tension control
system
comprising a first-stage thread tensioning device proximate, and downstream
from, the thread
capture assembly, further comprising a second stage thread tensioning device
spaced at least 3
meters, along the thread feed path, downstream from the first stage tensioning
device and
located within 3 meters of a locus where thread traversing the unwind and feed
system enters
such downstream operation.
In some embodiments, the invention further comprises an operator control
station
communicating with the thread tension control system, and adapted to send at
least one of
tension value, enable or disable switch signals, and alarm setpoint values to
the thread tension
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control system, and/or to receive at least one of feedback tension values and
status information
from the thread tension control system.
In some embodiments, the unwind and feed system :is operationally connected
into a
manufacturing system, the manufacturing system comprises a main controller,
the main
controller communicates with the unwind and feed system through the operator
control station.
In some embodiments, the main controller has an operator interface, and an
operator of
the manufacturing system can communicate with the thread tension control
system, and thereby
control the second-stage thread tensioning device, through the operator
interface.
In some embodiments, the third and fourth rolling capture devices have axes
which are
generally horizontal.
In some embodiments, the rolling brake is an electro-magnetic brake.
In a fifth family of embodiments, the invention comprehends an unwind and feed
system
adapted for overend unwinding of an elastic thread from a package of such
thread, and feeding
such unwound thread in a downstream direction, along a thread feed path, to a
downstream
operation, the unwind and feed system comprising a frame, including a thread
holder adapted to
hold a package of thread; a thread capture assembly located proximate such
thread holder, and
spaced from the thread holder a distance which facilitates the thread capture
assembly capturing
a loping thread which is being drawn overend off such package of thread, the
thread capture
assembly being effective to receive a loping thread from such package of
thread and to
substantially attenuate transverse movements of such loping thread, the
capture assembly
comprising a plurality of capture devices, all interaction of such thread with
the capture devices
comprising such thread contacting only moving surfaces of the capture devices;
and a thread
tension control system comprising (i) first-stage thread tensioning device
proximate and
downstream from the thread capture assembly, and (ii) second-stage thread
tensioning device
spaced at least 3 meters, along the thread feed path, downstream from the
first-stage tensioning
device and located within 3 meters of a locus where thread traversing the
unwind and feed
system enters such downstream operation.
In some embodiments, the invention further comprises a plurality of thread
guides
disposed along the thread path and between the thread capture assembly and the
second-stage
tensioning device, and all interaction of such thread with the thread guides
comprises such
thread contacting only moving surfaces of the thread guides.
In some embodiments, the thread guides are adapted' to move thread contact
surfaces of
the thread guides at surface speeds which approximate speeds of movement of
such thread.
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In some embodiments, the invention further comprises an operator control
station
communicating with the thread tension control system, and adapted to send at
least one of
tension value, enable or disable switch signals, and alarm setpoint value to
the thread tension
control system, and/or to receive at least one of feedback tension values and
status information
from the thread tension control system.
In some embodiments, the unwind and feed system is operationally connected
into a
manufacturing system, the manufacturing system comprises a main controller,
and the main
controller communicates with the unwind and feed system through the operator
control station.
In a sixth family of embodiments, the invention comprehends an unwind and feed
system
adapted and configured to feed thread to an entrance locus of a downstream
process at a
specified thread tension, the unwind system comprising a frame, the frame
comprising a plurality
of spool holders adapted and configured to hold spools of thread; and a thread
tension control
system comprising (i) a first-stage control system proximate the spool
holders, adapted and
configured to capture thread being drawn from such spools, and to apply an
initial controlled
level of tension on such thread, and (ii) a second-stage tensioning device,
positioned proximate
such manufacturing nip, the final tensioning device being adapted and
configured to apply a final
controlled level of tension on such thread proximate such entrance locus of
such downstream
process.
In some embodiments, the invention further comprises an operator control
station
communicating with the thread tension control system, and adapted to send at
least one of
tension value, enable or disable switch signals, and alarm setpoint value to
the thread tension
control system, and/or to receive at least one of feedback tension values and
status information
from the thread tension control system.
In a seventh family of embodiments, the invention comprehends a method of
unwinding
an elastic thread from a package of such thread in a manufacturing process,
and feeding such
unwound elastic thread in a downstream direction, along a thread feed path, to
a product
assembly operation. The method comprises drawing a continuous length of the
thread from the
package in an overend direction such that the thread leaves the package with a
loping action;
capturing the loping thread in a thread capture assembly; feeding the thread
from the thread
capture assembly to a locus where the thread enters the product assembly
operation; and
applying a terminal tensioning device to the thread so as to reach a desired
level of tension in
the thread, within 3 meters, along the thread path, of the locus where the
thread enters the
product assembly operation.
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In some embodiments, the terminal tensioning device comprises a second-stage
tensioning device applying a second-stage tension, the method further
comprising applying a
first stage tension to the thread, using a first-stage tensioning device,
located proximate the
thread capture assembly and at least 3 meters, along the thread path, from the
second-stage
tensioning device.
In an eighth family of embodiments, the invention comprehends a method of
manufacturing a product, using a manufacturing process, including
incorporating an elastic
thread, at a process entry locus, into the product being manufactured. The
method comprises
controlling the manufacturing process using a main controller, the main
controller having an
operator interface; unwinding the thread, from a package of such thread, in an
overend direction
and feeding the thread along a thread feed path to the process entry locus;
controlling tension in
the thread by processing the thread through a thread tensioning device; and
passing
communications, between the thread tensioning device and the main controller,
through a
secondary controller.
In some embodiments, a human operator can control operation of the thread
tensioning
device through the operator interface on the main controller:
In some embodiments, the secondary controller translates messages received
from the
main controller into protocol and/or format which can be read and understood
by the thread
tensioning device.
= In some embodiments, the secondary controller translates messages
received from the
thread tensioning device into protocol and/or format which can be read and
understood by the
main controller.
In some embodiments, the secondary controller transmits, and the thread
tensioning
device receives and responds to, numeric-value message signals.
In some embodiments, at least one of the secondary controller and the main
controller
transmits to the thread tensioning device, and receives from the thread
tensioning device on/off
message signals.
In some embodiments, the secondary controller transmits both numeric value
message
signals and on/off message signals.
In a ninth family of embodiments, the invention comprehends a method of
unwinding an
elastic thread from a package of such thread in a manufacturing process, and
feeding such
unwound elastic thread in a downstream direction, along a thread feed path, to
a product
assembly operation. The method comprises drawing a continuous length of ht
thread from the
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CA 02635258 2014-01-13
package in an overend direction such that the thread leaves the package with a
loping
action; capturing the loping thread in a thread capture assembly wherein the
thread engages
only moving surfaces; and feeding the thread from the thread capture assembly
to the
product assembly operation at an entry locus.
In a tenth family of embodiments, the invention comprehends a method of
unwinding
an elastic thread from a package of such thread in a manufacturing process,
and feeding
such unwound elastic thread in a downstream direction, along a thread feed
path, to a
product assembly operation. The method comprises drawing a continuous length
of the
thread from the package in an overend direction such that the thread leaves
the package
with a loping action; capturing the loping thread and feeding the thread along
the thread
path, to the product assembly operation, using only rolling thread guides,
except for thread
guides in any tension sensor.
In some embodiments, the invention further comprises passing the thread
through a
tension sensor, and any thread guide in the tension sensor comprises a rolling
thread guide.
In some embodiments, the invention further comprises applying a first-stage
tensioning device to the thread and thereby developing a first level of
tension in the thread
proximate the thread capture assembly, and applying a second-stage tensioning
device to
the thread and thereby developing a second different level of tension in the
thread within 3
meters of the entry locus where the thread enters the product assembly
operation, the
second-stage tensioning device being spaced from the first-stage tensioning
device by at
least 3 meters along the thread feed path.
In a preferred embodiment of the present invention there is provided an unwind
and
feed system adapted for overend unwinding of an elastic thread from a package
of such
thread, and adapted for feeding such unwound thread in a downstream direction,
along a
thread feed path, to a downstream process, the unwind and feed system
comprising: (a) a
thread package holder adapted to hold a package of such elastic thread; and
(b) a plurality
of thread guides disposed along the thread feed path, between such package of
such elastic
thread and such downstream process, the plurality of thread guides being
adapted to guide
such elastic thread as such elastic thread is moving along the thread feed
path, the plurality
of thread guides comprising (i) as first and second thread guides, respective
first and second
elongate rollers arranged at a generally common distance from the thread
package holder, in
upright orientations, the first and second elongate rollers being in close
proximity to each
other, and having axes of rotation parallel to each other, (ii) as a third
thread guide, a third
elongate roller disposed downstream, along the thread feed path, from the
first and second
thread guides, and (iii) as a fourth thread guide, a fourth elongate roller
located proximate
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the third roller, the third and fourth elongate rollers being disposed in
generally horizontal
orientations, and parallel to each other the third roller being between the
fourth roller and the
first and second rollers, such that a thread advancing from such thread
package first
encounters at least one of the first and second rollers, and subsequently
encounters the third
roller, and after encountering the third roller, encounters the fourth roller.
In a further preferred embodiment of the present invention there is provided
an
unwind and feed system adapted for drawing an elastic thread from a package of
such
thread, and feeding such unwound thread in a downstream direction, along a
thread feed
path, to a downstream process, the unwind and feed system comprising (a) a
thread
package holder adapted to hold a package of such elastic thread; (b) a
plurality of thread
guides disposed along the thread feed path, between the thread package holder
and such
downstream process, the plurality of thread guides being adapted to guide such
elastic
thread as such elastic thread is moving along the thread feed path, the
plurality of thread
guides comprising as first and second thread guides, first and second elongate
rollers
arranged at a generally common distance from the thread package holder, in
upright
orientations, the first and second elongate rollers being in close proximity
to each other, and
having axes of rotation parallel to each other, as a third thread guide, a
third elongate roller
disposed downstream, along the thread feed path, from the first and second
thread guides
as a fourth thread guide, a fourth elongate roller located proximate the third
roller, the third
and fourth elongate rollers being disposed in generally horizontal
orientations, and parallel to
each other, the third roller being between the fourth roller and the first and
second rollers,
such that a thread advancing from such thread package first encounters at
least one of the
first and second rollers, and subsequently encounters the third roller, and
after encountering
the third roller, encounters the fourth roller; and (c) a terminal tensioning
device which acts
on such elastic thread in the thread feed path within 3 meters of a locus
where the thread
feed path joins such downstream process, the terminal tensioning device being
adapted to
modify tension in such elastic thread.
In another preferred embodiment of the present invention there is provided an
unwind and feed system adapted for overend unwinding of a thread from a
package of such
thread, and feeding such unwound thread in a downstream direction, along a
thread feed
path, to a downstream process, the unwind and feed system comprising (a) a
package
holder adapted to hold a package of thread; (b) a thread capture assembly
adapted to
capture loping thread being drawn overend off such package of thread, the
capture
assembly comprising (i) first and second elongate rollers arranged at a
generally common
distance from the thread package holder, in upright orientations, the first
and second
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elongate rollers being in close proximity to each other, and having axes of
rotation parallel to
each other and reside in a common plane, and serving as initial contact
elements for such
thread being drawn overend off such package of thread, (ii) a third elongate
roller disposed
downstream, along the thread feed path, from the first and second elongate
rollers, and (iii) a
fourth elongate roller located proximate the third roller, the first, second,
third, and fourth
rollers having corresponding first, second, third, and fourth moving thread-
engaging surfaces
which are adapted to move in directions corresponding to longitudinal
direction of movement
of such thread when such thread-engaging surfaces are driven by motive forces
imposed on
such thread-engaging surfaces by such thread, and which are adapted to capture
such
loping thread, the third and fourth rollers being disposed in generally
horizontal orientations,
and parallel to each other, the third roller being between the fourth roller
and the first and
second rollers, such that a thread advancing from such thread package first
encounters at
least one of the first and second rollers, and subsequently encounters the
third roller, and
after encountering the third roller, encounters the fourth roller the thread
capture assembly
being effective to capture both horizontal and vertical vectors of such loping
thread, and (c) a
plurality of dynamic thread guides disposed along the thread feed path
downstream of the
thread capture assembly, and between the thread capture assembly and such
downstream
process.
In a still further preferred embodiment of the present invention there is
provided a
thread capture apparatus adapted to capture loping thread being drawn off a
package of
such thread, the thread capture apparatus comprising a plurality of thread
capture elements
which are collectively effective to capture such loping thread and to
substantially eliminate
such loping action in such thread downstream of the thread capture apparatus,
each the
thread capture element defining at least one thread engaging surface, such
thread engaging
surfaces being adapted to move in directions corresponding to longitudinal
directions of
movement of such thread across the respective the thread capture elements, the
thread
capture apparatus comprising, as a first the thread capture element, a first
rolling capture
element comprising a first elongate roller having a first the thread engaging
surface, the first
elongate roller being adapted and positioned to serve as an initial contact
element for such
thread being drawn from such package of thread, the first thread capture
element having a
first axis of rotation generally transverse to the longitudinal direction of
movement of such
thread across the first thread capture element, as a second the thread capture
element, a
second rolling capture element proximately downstream from the first rolling
capture
element, the second rolling capture element having a second the thread
engaging surface
and a second axis of rotation transverse to the first axis of rotation of the
first thread capture
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,
element, as a third the thread capture element, a third rolling capture
element proximate the
second rolling capture element, the third rolling capture element having a
third the thread
engaging surface and a third axis of rotation transverse to the first axis of
rotation of the first
thread capture element, the first elongate roller being disposed in a first
orientation wherein
the first axis of rotation is transverse to the general direction of advance
of such loping
thread before such thread reaches the first elongate roller, and wherein such
thread
encounters the first rolling capture element, as the initial contact element
after leaving such
package of thread, and wherein such thread, during normal dynamic ongoing
operation of
the thread capture apparatus, passes across a surface of the first elongate
roller, and from
the first elongate roller onto the second rolling capture element, turns
around the second
rolling capture element, and passes thence onto the third rolling capture
element, and turns
around the third rolling capture element.
In another preferred embodiment of the present invention there is provided a
thread
capture apparatus adapted to capture a thread being drawn from a source, the
thread
capture apparatus comprising a plurality of thread capture elements which are
collectively
effective to capture such thread, each the thread capture element defining at
least one
thread engaging surface, such thread engaging surfaces being adapted to move
in
directions corresponding to longitudinal directions of movement of such thread
across the
respective the thread capture elements, the thread capture apparatus
comprising, as a first
the thread capture element, a first rolling capture element comprising a first
elongate roller
having a first the thread engaging surface, the first elongate roller being
adapted and
positioned to serve as an initial contact element for such thread being drawn
from such
package of thread, the first thread capture element having a first axis of
rotation generally
transverse to the longitudinal direction of movement of such thread across the
first thread
capture element, as a second the thread capture element, a second rolling
capture element
proximately downstream from the first rolling capture element, the second
rolling capture
element having a second the thread engaging surface and a second axis of
rotation
transverse to the first axis of rotation of the first thread capture element,
as a third the thread
capture element, a third rolling capture element, the third thread capture
element having a
third the thread engaging surface and a third axis of rotation transverse to
the first axis of
rotation of the first thread capture element, and the second rolling capture
element being
between the third rolling capture element and the first rolling capture
element, the thread
capture apparatus being adapted to receive a thread advancing from such thread
package at
one of the plurality of thread capture elements, such that such thread
subsequently
encounters the second rolling capture element, and after encountering the
second rolling
capture element, encounters the third rolling capture element.
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' .
..
In a further preferred embodiment of the present invention there is provided a
tread
capture apparatus adapted to capture loping thread being drawn off a package
of such
thread, the thread capture apparatus comprising a plurality of thread capture
elements
collectively effective to capture such loping thread and to substantially
eliminate such loping
action in such thread downstream of the thread capture apparatus, each the
thread capture
element defining at least one thread engaging surface, such thread engaging
surfaces being
adapted to move in directions corresponding to longitudinal directions of
movement of such
thread across the respective the thread capture elements, the thread capture
apparatus
comprising, as a first thread capture element, a first rolling capture element
comprising a first
elongate roller having a first the thread engaging surface, the first elongate
roller being
adapted and positioned to serve as an initial contact for such thread being
drawn from such
package of thread, the first thread capture element having a first axis of
rotation generally
transverse to the longitudinal direction of movement of such thread across the
first thread
capture element, as a second the thread capture element, a second rolling
capture element
proximately downstream from the first rolling capture element, and along a
path of travel of
such thread, the second rolling capture element having a second the thread
engaging
surface and a second axis of rotation transverse to the first axis of rotation
of the first thread
capture element, and transverse to such path of travel of such thread, and a
rolling thread
guide positioned relative to the first and second thread capture elements, and
downstream
along such thread path from the second thread capture element, the first and
second thread
capture elements, and the rolling thread guide being so positioned and
oriented that such
thread, when drawn along such thread path by a force exerted at the rolling
thread guide,
approaches the first thread capture element from a first direction, wraps
about the first
thread capture element and leaves the first thread capture element in a second
different
direction directed toward the second thread capture element, wraps about the
second thread
capture element at least 90 degrees, and leaves the second thread capture
element in a
third different direction directed toward the rolling thread guide, and
traverses thence along
such third direction to the rolling thread guide.
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BRIEF DESCRIPTION OF THE DRAWINGS
FIGURE 1 shows a representative pictorial view of an unwind system of the
invention,
including unwind creel and first and second tensioning , devices, feeding
thread into a
manufacturing process line at a nip.
FIGURE 2 shows a pictorial view of an empty unwind Creel like that shown in
FIGURE 1.
FIGURE 3 shows an enlarged pictorial view of the unwind creel seen in FIGURE
1.
FIGURE 4 shows a pictorial representation of a thread capture system, in
juxtaposed
relationship with first and second spools of thread. =
FIGURE 5 shows a pictorial view of the thread capture system of FIGURE 4, and
is taken
at the circle "5" in FIGURE 4.
FIGURE 5A shows an enlarged pictorial view similar to that of FIGURES but
without the
mounting platform and with representation of first and second spools of thread
juxtaposed in
working position relative to the thread capture system.
FIGURE 5B shows a pictorial view of a thread capture system of the invention,
without
the mounting platform and without the spools of thread.
FIGURE 5C shows a top view of the thread capture system of FIGURE 4.
FIGURE 50 shows an enlarged top view of the thread capture system of FIGURE
5C,
without the spools.
FIGURE 5E shows an enlarged side elevation view of the thread capture system
of
FIGURES 5C and 5D.
FIGURE 6 shows an enlarged pictorial view of the final tensioning device.
FIGURES 7-10 provide illustrations of four control configurations which can be
used in
the invention.
The invention is not limited in its application to the details of construction
or the
arrangement of the components set forth in the following description or
illustrated in the
drawings. The invention is capable of other embodiments or of being practiced
or carried out in
other various ways. Also, it is to be understood that the terminology and
phraseology employed
herein is for purpose of description and illustration and should not be
regarded as limiting. Like
reference numerals are used to indicate like components. .
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DETAILED DESCRIPTION OF THE ILUSTRATED EMBODIMENTS
FIGURE 1 illustrates a typical layout of an unwind system 10 of the invention,
feeding
thread 12 into a nip 14, where the nip represents the location where the
thread joins a product
Turning now to FIGURES 2 and 3, creel 18 has a Metal e.g. steel frame 32 which
is
supported from the floor or other underlying surface by a plurality of feet 34
which are individually
Creel 18 can be thought of as having a front 48 and .a back 50. The back of
the creel
includes the back left upright support 38A and the back right' upright support
38B. The front of
the creel includes the front left upright support 38C and the front right
upright support 38D. Each
Referring now to FIGURES 2 and 3, the lower spool holder 52A1 on back left
upright
support 38A holds a full reserve spool 22A1 of thread while the lower spool
holder 52B1 on back
right upright support 38B holds an active spool 22B1 from which thread 12A is
illustrated as
being actively fed. Thus spool holders 52A1 and 52131 represent a first lower-
most tier of spool
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empty the thread feed is automatically transferred to the reserve spool
whereby the reserve
spool becomes the active spool and the empty spool is replaced by an operator.
The tail of the
feeding thread on the active spool is tied to the thread lead on the reserve
spool. The two spool
holders and spools thus work together to ensure that a first thread 12A is
always available for
feeding into the product assembly operation.
Similarly, spool holders 52A2 and 5262 represent a second tier of spool
holders, and
work with spools 22A2 and 22B2 to ensure constant availability of a second
thread 126 for
feeding into the product assembly operation. Spool holders 52A3 and 52133
represent a third tier
of spool holders, and work with spools 22A3 and 2263 to ensure constant
availability of a third
thread 12C for feeding into the product assembly operation. Spool holders 52A4
and 52B4
represent a fourth upper-most tier of spool holders, and work with spools 22A4
and 22B4 to
ensure constant availability of a fourth thread 120 for feeding into the
product assembly
operation.
A plurality of back braces 54, one at each tier of spools, on creel 18 (I) add
further rigidity
to the creel frame, (ii) provide a partial barrier to unintentional entrance
of a foreign object into
the creel from the back side of the creel, and (iii) hold the tied leading and
trailing ends of the
respective active and reserve spools on a given tier.
Turning now to FIGURES 3, 4, 5, 5A, 56, and 5C, a plurality of thread capture
assemblies 56 are mounted to the front of creel 18. Each thread capture
assembly is defined by
a mounting platform 58, a first pair of rollers 66, and at least one of a
second pair of rollers 70
which are oriented perpendicular to the rollers 66. Rollers 66 and 70 are
mounted to the
mounting platform. A magnetic brake 74, braking wheel 80, and a turning wheel
84 are also
mounted on the mounting platform.
A first one of the thread capture assemblies 56A cooperates with spoofs 22A1
and 2261
in capturing the thread 12A which is fed from the respective spool 22A1 or
2261. Thread
capture assembly 56A is supported from front upright supports 38C and 38D by a
mounting
platform 58. Mounting platform 58 has a front surface 60 which faces
frontwardly of the creel,
and a back surface 62 which faces in a backwardly-oriented direction, thus
facing toward the
spools of thread. A central aperture 64 (FIGURE 5) extends through the
mounting platform from
the front surface to the back surface. A first pair of vertically-oriented and
generally identical
upright rollers 66 is mounted closely adjacent front surface 62 of mounting
platform 58 by end-
closing brackets 68. The two rollers 66 extend in parallel directions and are
positioned closely
adjacent each other. Each of rollers 66 is located at generally the same
distance from front
surface 60 of mounting platform 58. Rollers 66 are of the same diameter and
their axes are in a
common imaginary plane which is parallel to front surface 60 of mounting plate
58. The
=
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opposing ends of both rollers 66 are received in brackets 68.! Brackets 68
extend between the
respective ends of the rollers 66 and are mounted to mounting platform 58.
A second pair of horizontally-oriented rollers 70, generally identical to
rollers 66, is
mounted closely adjacent, and frontwardly of, the first pair of rollers 66 by
end-closing brackets
72. The two rollers 70 extend in parallel directions and are positioned
closely adjacent each
other. In the illustrated embodiment, rollers 70 are of the same diameter,
each as the other, and
their axes are in a common imaginary plane which extends generally
horizontally, and
perpendicular to front surface 60 of the mounting plate. The opposing ends of
both rollers 70
are received in brackets 72. Brackets 72 extend between the respective ends of
the rollers 70
and are mounted to platform 58. =
In the illustrated embodiment, rollers 66 and rollers 70 are all of common
specification,
including for example and without limitation, common diameter, e.g. 0.5 inch
(13 millimeters),
common length, e.g. 2.5 inches (10 centimeters), common material of
construction, e.g. ceramic,
common suspension bearings, and the like. Thus, a thread 12 experiences
similar surface
effects and resistances in traversing any of rollers 66,70. In the
alternative, horizontal rollers 70
are of e.g. lesser diameters than rollers 66 so as to achieve reduced stopping
inertia. Horizontal
rollers 70 can also vary in other particulars from rollers 66 so long as the
collective set of rollers
66 and 70 effectively capture the loping thread.
Referring now to FIGURES 5B and 5C, an adjustable magnetic hysteresis brake 74
is
mounted to the front surface of mounting platform 58. As illustrated in FIGURE
5E, brake 74 has
an output shaft 76 extending frontwardly, and in a horizontal orientation,
from brake 74. A
braking roller/wheel 78 is mounted to shaft 76, for rotation with shaft 76.
Braking wheel 78 has a
groove 80 at its outer circumference. Groove 80 receives and guides a thread
which traverses
the wheel. In the illustrated embodiments, groove 80 resides in a vertical
plane which extends
upwardly from approximately a front-most tangent to the front-most one of
horizontal rollers 70.
A groove 82 in grooved turning wheel 84 resides in an imaginary plane which is
slightly
displaced, away from mounting plate 58, relative to wheel 78, such that a
thread traversing wheel
78 can, in general, travel to and traverse groove 82 without touching the
thread which is feeding
into wheel 78. In order to accomplish such thread-to-thread clearance when the
thread is under
tension, groove 82 is sufficiently narrow at its control depth to provide the
required degree of
lateral thread control.
A separate thread capture assembly 56 is provided foil each tier of spools,
accordingly for
each thread which is to be drawn/unwound from creel 18 and fed to
manufacturing line 16.
Thus, in the embodiment illustrated in e.g. FIGURE 3, four thread capture
assemblies are
provided to capture and control simultaneous traverse of four threads 12 from
creel 18.
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A mast 86 extends upwardly from the front top brace in creel 18. Four turning
wheels 88
=
(FIGURE 2) are mounted on a turning wheel assembly 90 wklich is mounted at the
top of mast
86. Turning wheels 88 are mounted so as to have axes of rotation oriented so
as to turn threads
12 coming from the respective turning wheels 84 in a desired direction. In the
illustrated
embodiments, the axes of turning wheels 84 are oriented horizontally, and turn
threads 12
across the aisle or walkway 92 which passes between creel '18 and
manufacturing line 16.
Delivery platform 20, and thus final tension control system 26, is mounted to
a machine
or other support on the manufacturing line, in close proximity to the nip 14
where the thread
enters the product assembly operation as an element in the goods being
manufactured on the
manufacturing line_ Thus, tension control system 26 can be mounted on a stand-
alone support
frame, can be mounted on the frame of a machine already existent in the
manufacturing line, or
can be mounted on any other convenient support available at the desired
location.
A second mast 94 can extend upwardly above delivery platform 20 to
approximately the
same elevation as mast 86 on creel 18. Mast 94 typically is not mounted to
delivery platform 20.
Rather, mast 94 is typically mounted to a frame somewhere in the vicinity of
delivery platform
20, and may be mounted on the same frame or machine on which the delivery
platform is
mounted.
Four turning wheels 96 are mounted on mast 94. In the alternative, and as
shown in
FIGURE 1, the assembly of turning wheels 96 can be mounted directly to
structure which is part
of one of the manufacturing line machines whereby that structure functions as
mast 94. Turning
wheels 96 are mounted so as to have axes of rotation oriented so as to turn
threads 12 coming
from first mast 86 in a desired downward direction so as to deliver the
threads to final tension
control system 26. In the illustrated embodiments, the axes of turning wheels
96 are oriented
horizontally, so as to accomplish the downward turn of the threads coming
across aisle 92.
Turning now to FIGURE 6, four final tension assemblies 100A, 100B, 100C, 100D
are
mounted to delivery platform 20. Each final tension assembly 100 includes an
incoming turning
wheel 102, a tensioning device 104, a tension sensor 106, and an outgoing
turning wheel 108.
Turning wheels 102 and 108 .are conventional grooved wheels mounted to
delivery
platform 20 on e.g. horizontal axes of rotation, and are typically the same
types of wheels as are
used for wheels 78, 84, and 96, thus to capture and guide a thread arriving
from a wheel 96 on
mast 94.
In the embodiment illustrated, tensioning device 104 is an actively driven
device which
expresses output at a rotationally-driven cylindrical outer surface 110.
Tension sensor 106
receives a thread passing therethrough, measures the tension on the thread,
and reports the
tension, or a tension variation, to a control driver 112 (FIGURE 1) which
computes changes in
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drive commands and communicates control commands to tensioning device 104
through a wire
connection, optionally through wireless communication channels. A wire
connection 114 is
shown to controller 104 and sensor 106
A suitable combination of tensioning device 104 and sensor 106, along with
control driver
112, is available as KTF 100RW from BTSR Company, OlOna, Italy. The "KTF"
system is
designed such that tensioning device 104 is actively driven by e.g. a 2-way
servo motor so as to
be able to increase or decrease tension in the thread as the thread passes
through a final
tension assembly 100. A braking-only controller 104 can be Used as desired in
a final tension
assembly, but accommodates a smaller range of acceptable incoming tensions on
the thread as
the thread enters the final tension assembly.
Since a typical manufacturing line where thread control systems of the
invention are
advantageously employed was designed and set up without contemplating use of a
control
system of the invention, there normally is not room to position a final
tension assembly close
enough to the manufacturing feed nip 14 that the thread can be fed directly
from outgoing turning
wheel 108 to the nip. Accordingly, one or more additional turning wheels, not
shown, are
typically used to guide the thread from outgoing turning wheel 108 to
manufacturing nip 14.
While choosing to not be bound by example, typically no more than 2 such
turning wheels are
used between outgoing turning wheel 108 and nip 14.
Typically, the distance between outgoing turning wheel 108, on delivery
platform 20, and
nip 14 is no more than about 3 meters, optionally no more than about 2 meters,
and is commonly
about 0.5 meter to about 2 meters. The distance between sensor 106 and
outgoing turning
wheel 108 is typically a matter of a few inches, such as about 1 inch to about
5 inches. Similarly,
the distance between tensioning device 104 and sensor 106 is a few inches,
such as about 1
inch to about 5 inches. By placing a second and final tension control assembly
close to the
manufacturing nip, the invention provides a substantially more uniform, and
more predictable,
tension on the thread as the thread enters the manufacturing nip. The tension
on the thread
entering the product assembly operation such as at nip 14 is more predictable,
and has fewer
variations and smaller variations. The thread thus enters the product assembly
operation,
including entering the product precursor, with a greater level of uniformity
of tension, whereby the
manufacturer obtains more control, tighter tolerances over variations in the
elongation and
retraction properties in the manufactured product.
The unwind system of the invention operates as follows. Referring to FIGURES
1,4, and
6, a leading end of a thread 12 is drawn from a spool 22 which is mounted on
creel 18, and
threaded through the thread capture assembly which is mounted on the
respective tier of the
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creel. Thus, the thread is threaded between vertical rollers 66, over the
first horizontal roller 70
and under the second horizontal roller 70.
The thread is passed, from the distal tangential surface of the second
horizontal roller 70,
upwardly and into a tangential relationship with the closest lateral edge of
wheel 78 on shaft 76
of the hysteresis brake. The thread is seated in groove 80, wrapped
approximately 270 degrees
around wheel 78 in a counterclockwise direction as seen in FIGURE 4, and
passed horizontally
away from wheel 78 and into tangential wrapping contact with a lower surface
of turning wheel
84. The thread is wrapped about 90 degrees about turning wheel 84, turning the
direction of the
thread from horizontal to upward. The thread is then drawn upwardly to turning
wheel assembly
90, about one of wheels 88, thence horizontally across the aisle 92 at an
elevated height, to and
about one of turning wheels 96, thence downwardly to one of turning wheels
102. The thread
traverses a turn in direction of about 90 degrees to about 135 degrees on
turning wheel 102, and
traverses thence to the respective driven tensioning device 104.
The thread is threaded typically about 270 degrees to about 310 degrees,
optionally more
or less, about outer surface 110 of the respective driven tensioning device.
The gripping,
friction characteristics of the outer surface of the tensioning device are
designed, adapted, and
configured to be able to grip the contemplated thread to be controlled in the
tension environment
employed as the thread enters the manufacturing nip. From the tensioning
device 104, the
thread is threaded through tension sensor 106, thence to outgoing turning
wheel 108. Now
referring to FIGURE 1, from turning wheel 108, the thread is typically
threaded over, under,
around, and/or through one or more additional thread guides in aligning the
thread for a non-
disruptive entrance into manufacturing nip 14.
Advantageously, threading eyes 118 or the like can be used adjacent entrance
and/or
departure loci of any of the various rolling thread guides downstream of
rollers 70. The function
of such threading eyes 118 is to hold the thread on the respective adjacent
thread guide when
the thread is slack, such as when the thread is initially threaded from a
spool 22 to nip 14.
However, such threading eyes are carefully positioned such that the travelling
thread, under
designed operating tension, does not touch such threading *eyes as the thread
is being drawn
along the thread path from a spool 22 to nip 14. An exemplary such threading
eye is shown as a
pigtail eye 118, adjacent the in-feed locus of wheel 78 in FIGURE 5.
Additional threads are so threaded, according to the design of the product
being
manufactured on the manufacturing line, along similar paths up to nip 14.
The threading can be done without application of any power to any of the
machines.
Indeed, no power need be connected to creel 18. Once all of the threads to be
employed at a
given time have been so threaded, power is applied to the driven roll in nip
14 causing a slowly
23
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WO 2007/079264 PCT/US2006/049672
driven rotation of the nip rolls, whereupon the threads are fed into the
manufacturing nip. As the
threads are advanced .into the manufacturing nip created by the slowly-turning
rolls, the threads
are drawn into the nip, thereby completing the threading process.
Once a thread has been captured at nip 14, any further advance of the rolls of
nip 14
imposes a draw on the thread, and progressively draws the thread into and
through the nip, and
thus into the manufacturing process. With the threads now in the nip, and
responsive to driving
of the rolls at the nip, the manufacturing operation is started up, including
progressively and
continuously drawing the threads into and through the nip. =
As thread is drawn through nip 14, the slack is taken up and the elastomeric
thread
stretches, to the point where the stretching force transfers all the way back
along the path of
travel of the thread, to the respective spool. As the draw force increases in
accord with rotation
of the rolls at nip 14, the draw on the thread eventually becomes sufficiently
great to cause
additional thread to be drawn from the spool. As the thread begins to pass
over the respective
rollers and wheels, the wheels and rollers take on their dynamic functions and
begin to rotate.
Further, as the thread comes up to operating tension, the thread loses all
contact with any static
threading eyes or other threading structures. As wheel 78 begins to rotate,
the magnetic force in
brake 74 begins to apply a braking force on wheel 78, thus applying a braking
force on the
respective thread 12.
As the thread begins to come off the active spool at an increasing rate, the
thread coming
off the spool begins to form what is known as a loop shape, hoop shape, jump
rope shape, or
balloon shape, which is associated with the drawing of the thread from about
the circumference
of the non-rotating, static spool. As the ballooning thread approaches
aperture 64, the confining
configuration of rollers 66 and rollers 70 dampens and suppresses the loping
activity of the
thread. Thus, the combination of upright rollers 66, horizontal rollers 70,
and the tension on the
thread, dampens the ballooning movement of the thread at first-stage control
system 24, and
takes captive the direction of advance of the thread. Namely, the rollers 66
capture and control
lateral movement of the thread, such that the thread arriving at the first-to-
be-encountered roller
70 still embodies substantial vertical movement, but little, if any, lateral
horizontal movement.
Given the tension on the thread, the first-to-be encountered horizontal roll
70 captures and
eliminates substantially all of the remaining vertical movement, whereby
substantially all of the
both vertical and the horizontal lateral movements of the thread coming off
the spool are
captured and nullified. The rollers 66, 70 thus channel the thread to advance
in the direction of
desired thread advance.
In, for example, FIGURES 5A and 5B, only a single vertically-oriented roller
66 is shown
so that the path of the thread can more easily be seen. However, the second
roller is used, as
24
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WO 2007/079264 PCT/US2006/049672
illustrated in FIGURE 5C, in orderfor first-stage control system 24 to provide
initial lateral control
of movement of the thread both when thread is drawn from the right spool
(FIGURE 50) as well
=
as when thread is drawn from the left spool.
The typical uncoated elastomeric fiber thread contemplated for use in this
invention is
uncoated spandex, which is quite tacky, such that the threads on a spool stick
together. Thus, a
thread on the surface of the spool is lightly held in its place by the
combination of underlying
threads, a small amount of tension, and optionally by laterally adjacent
threads. Since even the
threads on the surface of the spool of thread are not necessarily loose on the
spool, drawing the
thread from the spool requires a certain amount of force. For an as-spun spool
of uncoated
spandex thread, about 5 grams to about 20 grams of force are required to draw
the thread from
the spool. For a rewound spool of uncoated spandex thread, a lesser amount of
force, such as
about 2 grams of force, are required to draw the thread from the spool.
The instantaneous force required to take an incremental length of thread off
the spool
varies as the locus of attachment of the thread to the spool advances about
even a single wrap
of the thread about the spool. Typical force variations can range from as
little as no
force/tension where the thread is not attached at all, to up to about 30-40
grams of force. The
tension in a given roll, and from roll to roll varies in accord with the
composition of the spandex
thread, any processing material on the surface of the thread, the processing
conditions under
which the thread was deposited in the spool, and the environmental conditions
to which the
spool has been exposed since manufacture. Average tension, when drawing e.g.
680 decitex
uncoated spandex from a typical commercially-available spool of thread is, for
example and
without limitation, for an e.g. 10 minute test, about 6 grams at the outside
of a full spool, to about
12 grams as the residual thread being drawn approaches the spool core.
The purpose of the invention is to capture and control these substantial
variations in
tension, and the ballooning activity of the thread as the thread is being
drawn from the spool, and
to focus the energy in the thread, and the direction of travel of the thread,
so as to feed the
thread into nip 14 at a constant tension, consistent with the instantaneous
needs of the
manufacturing operation, as expressed at the manufacturing nip. By controlling
tension in the
thread closely adjacent the nip, the user is assured of a more consistent feed
of thread into the
product assembly process so as to produce consistently-tensioned finished
product exiting the
manufacturing operation. Namely, since the tension of the thread going into
the nip is effectively
controlled, and maintained close to a target thread tension, the retraction
properties of the
finished product which uses such stretched thread can be more precisely
targeted to the desired
retraction properties, and product can be manufactured with less variation in
retraction properties
over a given population of the finished product.
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By providing a separately defined path of travel for each thread, and by
guiding only one
thread with each thread guide, whether it be a roller or a wheel, a tensioning
device, or a tension
sensor, the tension of each thread can be separately monitored and controlled,
such that a
different thread tension can be targeted and obtained for any one thread, or
for different groups
of threads. Thus, each thread can be individually controlled such that the
tension on the thread
as the thread enters nip 14 can be controlled so as to be prediCtably
different from the tension on
any one or more of the other threads which are simultaneously being fed into
nip 14. Similarly,
each thread can be individually controlled such that the tension on the thread
as the thread
enters nip 14 can be controlled so as to be predictably the same as the
tension on any one or
more of the other threads which are simultaneously being fed into nip 14.
A typical path of travel from spool 22 to nip 14, typically across an aisle
92, is about 5
meters to about 20 meters, optionally about 10 meters to about 20 meters.
Thread 12
necessarily traverses a number of roller guides and/or wheel guides along its
path of travel, each
of which adds its incremental but rather nominal drag contribution to the
tension already on the
thread.
As the thread approaches thread capture assembly 56, the tension on the thread
has
historically, and using technology of the prior art, been about 2 grams to
about 40 grams of force,
and typically averages about 6 grams to about 12 grams.
An exemplary magnetic brake 74 useful in the invention is a 513 series
permanent
magnet hysteresis brake available from Magnetic Technologies, Oxford,
Massachusetts. Such
brake requires no external energy source and operates entirely on the basis of
the energy
expressed by the magnet forces generated internally by rotation of the brake.
Thus, as the
thread is drawn about wheel 78, wheel 78 begins to rotate, thus rotating shaft
76 and thus the
internal mechanism of brake 74. As the internal mechanism of brake 74 turns,
the
electromagnetic flux of the brake magnet exerts a retarding force urging
retardation of the speed
of rotation of shaft 76, and thus wheel 78. This retarding force applies a
braking force to retard
advance of the thread, with the result that the tension on the thread as the
thread leaves wheel
78 is desirably about 50 percent to about 80 percent of the final tension
which is desired of the
thread as the thread enters the manufacturing nip. If the actual tension is
not within the desired
range of tensions, a 513 series such brake can be manually adjusted to bring
the tension of the
thread leaving the brake into the specified range.
The actual desired tension leaving wheel 78 can and does vary depending what
other
drag forces are exerted on the thread as the thread traverses the path of
travel from spool 22 to
nip 14. For example, a rolling contact exerts less drag than a static contact.
A dirty bearing on a
rolling contact exerts more drag than a rolling contact which has a clean
bearing. A tacky or
=
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high-friction thread-contacting surface on either a rolling contact or a
static contact exerts more
drag than a clean surface. At least dirt and friction drag factors can change
during a thread
feeding operation.
In the illustrated embodiments, and as a characteristic feature of unwind
systems of the
invention, all thread contacts with the exception of the recited sensor 106,
but including all thread
guides, present rolling contact surfaces to the thread. Thus, all thread
contact is a rolling surface
contact, thereby applying only minimal resistance, drag on the thread as the
thread advances
along its path of travel.
This is in stark contrast with prior art unwind systems which guide the thread
under
tension through one or more static thread-directing guides which are routinely
in constant contact
with the thread as the thread is being drawn under tension, including in some
cases after the
thread has passed a tensioning device on the creel, whereby the tension on the
thread as the
thread leaves the tensioning device on the creel is no more than about 40
percent of the final
tension, with the remaining tension being added by the uncontrolled and
unpredictable friction of
the turning devices which are arrayed along the thread path.
Since, in the invention, a reduced amount of drag is imposed on the thread by
the rolling
thread contacts, since the tension desired at manufacturing nip 14 is
independent of any tension
experienced by the thread ahead of the manufacturing nip, a higher amount of
tension can be
applied to the thread at creel brake 74 without exceeding safe thread tension
limits downstream
of the brake, along the thread path.
Thus, higher target thread tension levels of about 50 grams to about 80 grams
can be
applied in the invention as the thread leaves the creel with n exemplary 680
decitex thread
where the target tension going into nip 14 is about 100 grams to about 110
grams. Thus, the
rise in tension between brake 74 and tensioning device 104 is typically less
than 110-50 = 60
grams, optionally less than 110-80 = 30 grams for such 680 decitex thread.
Given the higher relative tension which can be applied to thread 12 as the
thread leaves
the creel, the operator can achieve more precise control of the thread as the
thread traverses the
path toward tensioning device 104, where the final tension level is applied to
the thread. Thus,
first-stage tensioner 74 does more than simply damp out major tension spikes
in the thread. The
higher tension between the first and second-stage tensioners can better absorb
slack in the
thread which occurs as the thread comes off the spool. Further, since
additional tension can be
applied to the thread at brake 74, and in light of the use of the second stage
tensioner, at least
some of the additional tension applied by brake 74 extends along the thread to
the second-stage
tensioner, whereby both sudden increases and sudden decreases in tension in
the thread
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anywhere along the thread path between the first and second tensioners, can be
more readily
absorbed in the feed system.
Returning now to further brief discussion of thread capture assembly 56, the
reduced
drag on the thread at rollers 66,70, as compared to a static eye, imposes a
reduced level of drag
on thread 12, and the thread has less tendency to stick to the surface of the
respective guide
member, as the thread enters the capture assembly. Given the reduced tendency
to stick on the
capture assembly member, given that all contact at the capture assembly is
rolling contact, the
thread passes through the capture assembly up to brake 74, wheel 78, with less
drag on the
thread, whereby the angle-related limitation on location/angle of the spool,
as expressed in e.g.
US Patent 6,670,054 Heaney et al, is not important, in the instant invention,
to the ability to get
thread 12 through the thread capture process without breaking the thread.
Rather, any angle
which can effectively feed the thread to rollers 66 is acceptable in the
invention.
Similarly, the distance limitations expressed in Heaney et al '054 are no
longer limitations
on the ability to feed thread to the capture assembly without breakage of the
thread. Further, the
degree of tackiness, as expressed in Heaney et al '054, is not a factor in
ability of the thread to
be captured by capture assembly 56.
Accordingly, the only limitation on distance between the closest portion of
the spool of
thread and the capture assembly is that enough room must be provided for front-
mounting the
spool on a spool holder 52. Indeed, where the spool holder is designed and
configured to be
detachable from its upright support 38 for mounting of a spool on the spool
holder, the distance
between the front of the spool and rollers 66 can be as little as, in some
instances, about 0.2
meter. Distances of 0.25 meter, 0.30 meter, 0.35 meter, and 0.38 meter, and
all distance
increments in between, all of which are less than the distances contemplated
by Heaney et al
'054, are all possible and contemplated for use in the invention. The greater
distances, which
are limits in the prior art, and which are practiced in the prior art, are not
limits in the invention,
but can be employed if and as desired.
Regarding the spool angle, while an angle larger than those recited in the
prior art can be
used, for purposes of efficiently using manufacturing floor space, the creel
is kept as compact as
practical, whereby the angle between a projected axis of aperture 64 and the
axes of the
respective spools 22 is typically about 22 degrees, as illustrated generally
in FIGURE 5C.
While the creel as illustrated herein shows capacity for feeding four threads
simultaneously, and a total of eight spool holders, the creel can be expanded
both laterally and
vertically to accommodate a greater number of spools on the creel, and a
corresponding greater
number of threads being fed simultaneously. Similarly, as desired, the spool
capacity can be
reduced if desired to handle fewer than 4 threads and 8 spools. In general the
ratio of the
28
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WO 2007/079264 PCT/US2006/049672
number of spools which. can be held on the creel is twice as great as the
number of threads
which are to be fed simultaneously. Thus, for each thread being fed, one
active spool will be
feeding the thread, and an adjacent spool holder is available to hold the
reserve spool to which
the feeding is transferred automatically when the active spool is empty.
If and as desired, brake 74 can be an actively and externally energized driven
brake
rather than a passive brake energized only by magnetic forges emanating from a
permanent
magnet.
As mentioned earlier, all thread guides and controls, except for the exemplary
tension
sensor, are rolling devices. The sensor above mentioned from BTSR Italy does
employ static
guides in collecting tension data for feed to control driver 112. If and as
desired, a sensor having
rolling guides can be used instead, whereby all of the guides and other thread
contacts are
rolling contacts.
It is noted that, in the invention, the capture assembly uses two pairs of
rollers 66, 70, on
perpendicular axes, both axes being perpendicular to the direction of travel
of the thread, to
serve as a balloon damper, thus to dampen out the loping, jump-roping
ballooning of the thread,
and thereby to capture and tame the lateral movements and tension spikes in
the thread and to
bring the thread under control for further processing of the thread according
to direction of travel
and quantity and intensity of tension variations.
By using only rolling contacts so that the tension leaving the creel can be
e.g. 50 to 80
grams, an increased level of control is exerted over tension variations in the
thread. Namely, the
ability to hold tension in the thread at a higher level for a longer distance
provides an increase in
the ability to control, and dissipate, tension spikes which enter the thread
as the thread is being
drawn off the spool. So, while the thread in the invention starts along its
path from the spool with
a conventional quantity of tension variations and spikes, the.ability to apply
increased level of
tension to the thread, over a longer distance, compared to conventionally
known technology,
gives greater control of tension leaving the creel. By adding a second
tensioning device
proximate the entrance of the thread into the manufacturing process, control
of thread tension
becomes less dependent on what happens to the thread up.-stream of the second
tensioning
device, and more dependent on the actual tension imparted to the thread by the
second
tensioning device.
So to some extent, the increased tension upstream of a final tension assembly
100 is
less important to the final tension and largely used to get better, more
positive control of the
thread so as to prevent the thread from e.g. jumping out of the grooves in the
respective turning
wheels, and the like. Nevertheless, the greater tension level between brake 74
and tension
assembly 100 does enable better control of the tracking of the thread along
its path of travel.
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Accordingly, it is advantageous, as discovered in the invention, to apply a
first-stage
tension control to the thread close to the thread package/spool 22, in
combination with a second-
stage tension control close to the manufacturing nip. The first-stage control
as at brake 74
provides increased control of the traverse of the thread over tie path of
travel e.g. across aisle
92 to final tension assemblies 100. The final application of tension control
provides precise
control of the tension going into the nip, with only minor variations as the
thread passes over the
last Ito 3 guides in getting from tension assembly 100 to the nip.
If and where room permits in a product assembly operation to which thread is
to be fed,
tension assembly 100 is desirably positioned and aligned so as to feed the
thread from the
For effective use of both a first-stage tension control and a final-stage
tension control, the
two control devices are typically separated by at least 0.25 meters,
optionally separated by at
least 1 meter, also optionally separated by at least 2 meters, or 3 meters, or
more depending on
The final tension control as at tension assemblies 100 can be designed and
specified to
function only as a brake. On the other hand, the tensioning device 104 can be
powered by e.g. a
servo motor so as to have the ability act as either a brake, thereby to
increase tension on the
thread, or as a drive motor, thereby to decrease tension on the thread. Where
the final
The unwind and feed systems of the invention can be Controlled using a variety
of control
systems. In the simplest control system, an unwind and fed system of the
invention can
operate as a stand-alone system which does not have any communication with the
overall
CA 02635258 2008-06-25
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to draw tension generated at nip 14 of the manufacturing operation, starting
when the
manufacturing operation is started up. In that case, all tension targets,
status information such
as thread breaks, and the like, are handled manually by an operator who inputs
commands at
each tensioning device.
As a step in up-grading system control, data and switching commands can be
handled by
a stand-alone operator control station which can enable, an operator to
control multiple
tensioning devices from a single operator control station. A Suitable such
interface is available
as model HE-XE105 from Horner APG, Indianapolis, Indiana. Such stand-alone
operator control
station can be used to send various commands to multiple tensioning devices;
such commands
as tension setpoint value, enable/disable switching, and alarm setpoint
values. In addition, the
operator control station can receive feedback tension values and status
information, from which
the operator control station can generate alarms. In addition, the operator
control station can be
used to provide enable/disable commands to any or all of the tensioning
devices.
Control of the unwind and feed systems of the invention can also be integrated
with the
overall manufacturing operation by providing communication between the
operator control
station, as a secondary interface device, and the main PLC which is operating
the overall
manufacturing operation. A first such integrated communication and control
system is illustrated
in FIGURE 7. In the system of FIGURE 7, the operator control station is
numbered 120 and the
main PLC is numbered 122. Four final tension assemblies 100A, 100B, 100C, and
100D are
illustrated. Any desired number of tension assemblies can be used as indicated
by the number
of threads which are to be fed into the manufacturing operation.
Still referring to embodiments represented by FIGURE 7, the operator control
station
functions largely as a communications facilitator. Operator control station
120 receives a
message from the main PLC over a communications link 124, and modifies the
protocol and/or
the format of the message, for example and without limitation scales the
information in the
message, organizes the information in the message, or converting units of
measure in the
information. The operator control station 120 sends the modified message to
the tension control
assemblies over a serial communications link 126. For example, the main PLC
sends setpoint
values in a protocol and/or format which cannot be received and understood by
the tension
control assemblies 100. The operator control interface translates the setpoint
values from the
PLC into a protocol and/or format which can be read and understood by the
tension control
assemblies, and sends the modified message to the tension control assembly.
Similarly, the
tension control assemblies 100 send feedback and status values over
communications link 126
in protocol and/or format which cannot be received and understood by the main
PLC 122.
Operator control station 120 translates the feedback and status values into a
protocol and/or
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format which can be read and understood by main PLC 122, and sends the
translated
information to the main PLC over communications link 124. '
In the embodiments illustrated in FIGURE 8, operator control station 120
continues to
function in a translation and communications capacity as in FIGURE 7. In
addition, switching
information/commands such as alarm trigger signals and enable/disable signals
are fed back
and forth directly between the main PLC and the tensioning devices 100A, 100B,
100C, 100D
through communications links 128A, 128B, 128C and 128D. Since the information
transmitted
over communications links 128A, 128B, 128C, and 128D are on/off, switching
commands only,
no specific protocol and/or format per se is needed to interpret such
commands, whereby the
translation capabilities of operator control station 120 are not needed, and
the communications
links can go directly to main PLC 122 without passing through operator control
station 120 for
translation purposes.
In the embodiments illustrated in FIGURE 9, all communications between the
main PLC
and the tension control assemblies 100 passes through operator control station
120. However,
all communications from operator control station 120 to the tension control
assemblies is sent as
on/off switching signals. The illustrated KTF tension control assemblies have
a default tension
setpoint. In the embodiments illustrated FIGURES 7 and 8, the main PLC and the
operator
control station send specific values to the tension control assemblies as a
single command. In
the embodiments of FIGURE 9, since only on/off signals are sent, e.g. a
tension setpoint value
command is sent as a series of "up" or "down" commands, each of which
increments the tension
setpoint up or down by one unit of measure. In the alternative, the operator
interface can
translate the information from the main PLC into analog signals and
communicate to and from
the tension control assemblies using such analog signals. Any such analog
signals received
from the tension control assemblies are translated by the operator control
station into digital
signals, which are then communicated to the main PLC.
In the embodiments illustrated in FIGURE 10, all communications flow through
the
operator control station. Value signals are translated by the operator control
station as in
FIGURES 7 and 8. On/off signals such as the enable/disable switch signals, and
alarm on/off
signals are sent and received by the operator control station. The operator
control station can
send the raw data back to the main PLC, or can send only summary information
to the main
PLC.
In any embodiments which use an operator control station 120, optionally with
communications to the main PLC, data sent to and received from the tension
control assemblies
can be stored in a memory device, such as for historical purposes. Such memory
device can be
part of the main PLC, part of the operator control station, a=stand-alone
memory device, or a
=
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memory device embodied elsewhere, either on-site or off-site with respect to
the manufacturing
operation. Such historical information can be used e.g. for analyzing
engineering issues, for
analyzing safety issues regarding the manufactured product; or the like.
In light of the above discussion of FIGURES 7-10, a secondary controller 120
can be
used to pass setpoints from the main PLC to the tensioning devices. The
secondary controller,
in turn, passes feedback and status information from the tension control
devices to the main
PLC. This secondary controller can merely act as an interface device or
protocol converter
between the main PLC and the tension control devices. Other timing, control,
and monitoring
functions also can be performed in such secondary controller. In an
alternative embodiment, the
communications conversions take place inside the main system PLC so that the
main PLC can
directly communicate to the tensioning devices.
Communications Between Main System PLC and Secondary Sub-System PLC
Information which can be communicated from the main PLC to the secondary
controller
includes, but is not limited to, various control setpoints such as
Tension Setpoints. Each tension device can have a unique setpoint. Groups of
devices
can have the same tension setpoint.
Tension Deviation Alarm Tolerance. The amount of deviation from the tension
setpoint
which is allowable as sensed in the tensioned thread.
Startup Time. A greater tension deviation can be allowable while the
production line is
ramping up to speed.
Production Line Speed. Different tension settings can be used for different
line speeds
such as thread up, slow run, and normal run. The secondary controller
communicates the
proper tension setpoints to the tensioning devices based on the speed of the
main production
line.
Device selection/activation/disabling. Not all tensioning devices are used for
all product
configurations. Accordingly, some tensioning devices can be disabled in some
configurations of
the manufacturing operation.
Typical information which must be communicated from the secondary interface
controller
to the main PLC includes
Condition/Status of the tensioning devices such as tension or other alarms,
drive
temperature, drive current.
Tension Feedback. Actual feedback value from individual ones of the tension
sensors.
Methods of communications between main system PLC and secondary sub-system
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interface controller include any one of the common industrial communications
protocols. Such
protocols can be used to pass information between the mail PLC and the sub-
system interface
controller. Useful protocols include but are not limited to
Ethernet,
Device Net,
Modbus RTU,
Control Net,
Profibus,
CC-Link,
CAN bus, and
ASCII serial communications.
An alternate method of communication between main system PLC and secondary sub-
system interface controller:
The setpoint, feedback, and status values can also be communicated between the
main
PLC and the secondary sub-system controller using analog inputs and outputs.
For example, a
0-10VDC analog output can be used by the main PLC to command tension setpoint
of 0-200
grams. An analog input on the secondary controller can read the tension
setpoint value from the
main PLC and use the tension setpoint value in the main PLC to set the tension
setpoint in the
tensioning devices. Similarly, a 0-10VDC analog output from the secondary
controller can be
used to communicate tension feedback or system health to an analog input on
the main system
=
PLC.
Communications Between Secondary Controller And Tensionino Devices
Serial Communications:
A typical baby diaper production line has 4-12 tensioning devices. A typical
adult
incontinent product production line has up to e.g. about 72 tensioning
devices, or more. Using a
proprietary communications protocol available for the KTF tensioning devices,
from BTSR, the
secondary sub-system controller can communicate setpoint Values to each
tensioning device. It
is possible for one sub-system controller to communicate with several hundred
tensioning
devices, as needed. Use of such secondary controllers enables substantial
reduction in the
physical wiring between the controller and the tensioning devices, compared to
other methods of
controlling setpoints.
Increase/Decrease Pulses:
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Some stand-alone tensioning devices such as the BT R brand KTF-RW model allow
for
the pre-programmed tension setpoint to be temporarily modified when the system
is active using
physical digital inputs. After motion begins, inputs for "increase" or
"decrease" can be pulsed on
and off to increment or decrement the tension setpoint. Each pulse can change
the active
tension setpoint by a pre-determined value. For example, if the pre-programmed
tension
setpoint is 100 grams, the "increase" input can be pulsed 5 times to
temporarily change the
tension setpoint to 105 grams.
Analog Inputs / Outputs:
Some stand-alone tensioning devices can accept analog signals such as 0-10VDC
or4-
20mA as tension setpoints. The secondary sub-system interface controller can
receive control
setpoint demand information from the main system PLC and convert the demand
values to
analog control signals. The analog control signals can be sent to the
individual tensioning
devices, e.g. KTR-RW, to be used as tension setpoints. '
Enable / Disable Tensioning Devices:
Most tensioning devices require some sort of enable/disable signal to reduce
or disable
the tensioning mechanism (motor, brake, etc.) when the production line is not
moving. This
enable/disable signal can be a physical input or it can be sent via a serial
communications
signal.
Monitor Alarm Output from each Device:
Secondary controller 120 can monitor a physical alarm output from each
tensioning
device. This alarm output can indicate a tension error, broken or missing
thread, drive fault,
sensor fault, or some other tension system fault. The secondary controller
communicates
actionable alarm signals to the main PLC. The main PLC makes go/no-go
decisions, and issues
corresponding commands, based on such alarm signals.
The use of a secondary sub-system controller to provide inputs and outputs to
control the
pulsing logic and alarm monitoring for such control configuration reduces the
installation time
and expense, compared to using the main system PLC for such functions.
Sub-System Controller Optional Features
Tension Data Logging:
The feedback from the tension sensors can be used to log the actual tension of
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CA 02635258 2008-06-25
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individual thread which is being fed into the manufacturing process. This data
can be used to
verify the quality and consistency of the products which are being made with
the production
process.
Alarm Logging:
The secondary controller can be used to detect alarm or warning conditions
such as:
tension outside allowable deviation limits, missing or broken threads, drive
faults, and the like.
The date, time, and frequency of these events can be logged for later
evaluation. The logged
data can be stored in the memory of the secondary controller, or it can be
stored on a removable
memory storage device. It may also be uploaded to the main PLC 122, or to a PC
or other
device having available data storage capability.
Recipe Storage:
In certain product configurations, different tensioning devices can have
different tension
setpoints. Such differences can provide contoured/varying tension, a tension
variation, a tension
gradation, across a product, or can compensate for mechanical differences in
the production
line. Different products produced on the same line can specify the use of
different setpoint
values on each tensioning device. Such groups of control setpoints can be
stored as "recipes" in
the secondary controller. When a new product is to be run on the production
line, it is only
necessary for the main system PLC to select from one of the saved "recipes"
rather than
transmitting all of the setpoint values for each of the tensioning devices.
The corresponding
setpoint values in the recipe are then communicated from the secondary
controller to the
respective tensioning devices.
Speed Variable Tension Settings:
It is often desirable to use different tension setpoints at different machine
speeds. For
example, during initial start-up, a relatively lower tension value reduces the
likelihood of thread
breaks. Similarly different tension setpoints can provide optimum performance
at jog speed vs.
full run speed. The secondary controller can automatically adjust the
setpoints of the tensioning
devices based on production line speed. =
=
Communications Interface Device, General capabilities of the secondary
controller
An industrial control device, such as secondary contrqller 120, which can
communicate
both with industry standard PLC's and with stand-alone tensioning devices such
as KTF's.
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The secondary controller can communicate with industrial PLC's using a
standard
industrial communications protocols such as
Ethernet
Control Net
Device Net
Profi bus
Modbus
ASCII serial
CC-Link
DF-1
DH+
RS-232
RS-485
RS-422
The secondary controller can use analog inputs and outputs to communicate
values of
setpoints, feedback, and/or status.
The secondary controller can use digital input/output to select preset control
setpoints
and to communicate status and alarm conditions with main PLC 122.
The secondary controller can communicate with the tension control device using
serial /
network communications such as:
RS-232
RS-485
RS-422
including use of an optional protocol converter to convert standard RS-232 to
other
protocols such as proprietary 9-bit RS-485.
Digital outputs from the secondary controller can be used to increase or
decrease tension
relative to a preset value which is stored in the memory of the tension
control device.
Digital output from the secondary controller can be used to enable, disable,
reset, and/or
adjust alarm monitoring functions in the tension control devices.
Digital output from the secondary controller can be used to enable or disable
one or more
selected ones of the tension control devices, thereby to operationally
deactivate a tension control
device from the manufacturing operation, or to operationally activate a
tension control device into
the manufacturing operation.
Digital inputs to the secondary controller can be used to monitor the unwind
and feed
system for alarm signals on the tension control devices.
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= .
.,
The secondary controller can provide analog outputs and receive analog inputs.
Exemplary such analog signals include 0-10VDC, 0-20mA, 4-20mA analog signals,
which
can be used to set tension setpoints in tension control devices.
Additional functions of the secondary controller, which functions as a
communications interface device/multiple position tension controller, include
Distribution of all control setpoints to multiple tension control devices,
Monitoring of tension feedback values to determine if actual tensions are
within
allowable tolerances relative to tension setpoints,
Storing multiple groups of control setpoints or parameter recipes for various
product
configurations,
Monitoring alarm status for multiple tension control devices,
Logging history of alarms including but not limited to date, time, and
frequency of
alarms for each tension control device, and
Communicating tensioning device status to the main controller to indicate
alarm or
warning conditions which may require operator intervention or the stopping of
the
manufacturing operation.
The invention further contemplates methods of controlling thread unwind and
feed
operations using the secondary controller, either alone or in combination with
a main PLC
which controls the overall manufacturing operation.
The scope of the claims should not be limited by the preferred embodiments set
forth
herein, but should be given the broadest interpretation consistent with the
description as a
whole.
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